Methods of forming integrated assemblies include stacked memory decks

ABSTRACT

Some embodiments include an integrated assembly having a first deck which has first memory cells, and having a second deck which has second memory cells. The first memory cells have first control gate regions which include a first conductive material vertically between horizontally-extending bars of a second conductive material. The second memory cells have second control gate regions which include a fourth conductive material along an outer surface of a third conductive material. A pillar passes through the first and second decks. The pillar includes a dielectric-barrier material laterally surrounding a channel material. The first and fourth materials are directly against the dielectric-barrier material. Some embodiments include methods of forming integrated assemblies.

TECHNICAL FIELD

Integrated assemblies which include stacked memory decks, and methods offorming integrated assemblies.

BACKGROUND

Memory provides data storage for electronic systems. Flash memory is onetype of memory, and has numerous uses in modern computers and devices.For instance, modern personal computers may have BIOS stored on a flashmemory chip. As another example, it is becoming increasingly common forcomputers and other devices to utilize flash memory in solid statedrives to replace conventional hard drives. As yet another example,flash memory is popular in wireless electronic devices because itenables manufacturers to support new communication protocols as theybecome standardized, and to provide the ability to remotely upgrade thedevices for enhanced features.

NAND may be a basic architecture of flash memory, and may be configuredto comprise vertically-stacked memory cells.

Before describing NAND specifically, it may be helpful to more generallydescribe the relationship of a memory array within an integratedarrangement. FIG. 1 shows a block diagram of a prior art device 1000which includes a memory array 1002 having a plurality of memory cells1003 arranged in rows and columns along with access lines 1004 (e.g.,wordlines to conduct signals WL0 through WLm) and first data lines 1006(e.g., bitlines to conduct signals BL0 through BLn). Access lines 1004and first data lines 1006 may be used to transfer information to andfrom the memory cells 1003. A row decoder 1007 and a column decoder 1008decode address signals AO through AX on address lines 1009 to determinewhich ones of the memory cells 1003 are to be accessed. A senseamplifier circuit 1015 operates to determine the values of informationread from the memory cells 1003. An I/O circuit 1017 transfers values ofinformation between the memory array 1002 and input/output (I/O) lines1005. Signals DQ0 through DQN on the I/O lines 1005 can represent valuesof information read from or to be written into the memory cells 1003.Other devices can communicate with the device 1000 through the I/O lines1005, the address lines 1009, or the control lines 1020. A memorycontrol unit 1018 is used to control memory operations which are to beperformed on the memory cells 1003, and utilizes signals on the controllines 1020. The device 1000 can receive supply voltage signals Vcc andVss on a first supply line 1030 and a second supply line 1032,respectively. The device 1000 includes a select circuit 1040 and aninput/output (I/O) circuit 1017. The select circuit 1040 can respond,via the I/O circuit 1017, to signals CSEL1 through CSELn to selectsignals on the first data lines 1006 and the second data lines 1013 thatcan represent the values of information to be read from or to beprogrammed into the memory cells 1003. The column decoder 1008 canselectively activate the CSEL1 through CSELn signals based on the AOthrough AX address signals on the address lines 1009. The select circuit1040 can select the signals on the first data lines 1006 and the seconddata lines 1013 to provide communication between the memory array 1002and the I/O circuit 1017 during read and programming operations.

The memory array 1002 of FIG. 1 may be a NAND memory array, and FIG. 2shows a schematic diagram of a three-dimensional NAND memory device 200which may be utilized for the memory array 1002 of FIG. 1. The device200 comprises a plurality of strings of charge-storage devices. In afirst direction (Z-Z′), each string of charge-storage devices maycomprise, for example, thirty-two charge-storage devices stacked overone another with each charge-storage device corresponding to one of, forexample, thirty-two tiers (e.g., Tier0-Tier31). The charge-storagedevices of a respective string may share a common channel region, suchas one formed in a respective pillar of semiconductor material (e.g.,polysilicon) about which the string of charge-storage devices is formed.In a second direction (X-X′), each first group of, for example, sixteenfirst groups of the plurality of strings may comprise, for example,eight strings sharing a plurality (e.g., thirty-two) of access lines(i.e., “global control gate (CG) lines”, also known as wordlines, WLs).Each of the access lines may couple the charge-storage devices within atier. The charge-storage devices coupled by the same access line (andthus corresponding to the same tier) may be logically grouped into, forexample, two pages, such as P0/P32, P1/P33, P2/P34 and so on, when eachcharge-storage device comprises a cell capable of storing two bits ofinformation. In a third direction (Y-Y′), each second group of, forexample, eight second groups of the plurality of strings, may comprisesixteen strings coupled by a corresponding one of eight data lines. Thesize of a memory block may comprise 1,024 pages and total about 16 MB(e.g., 16 WLs×32 tiers×2 bits=1,024 pages/block, block size=1,024pages×16 KB/page=16 MB). The number of the strings, tiers, access lines,data lines, first groups, second groups and/or pages may be greater orsmaller than those shown in FIG. 2.

FIG. 3 shows a cross-sectional view of a memory block 300 of the 3D NANDmemory device 200 of FIG. 2 in an X-X′ direction, including fifteenstrings of charge-storage devices in one of the sixteen first groups ofstrings described with respect to FIG. 2. The plurality of strings ofthe memory block 300 may be grouped into a plurality of subsets 310,320, 330 (e.g., tile columns), such as tile column_(I), tile column_(j)and tile column_(K), with each subset (e.g., tile column) comprising a“partial block” of the memory block 300. A global drain-side select gate(SGD) line 340 may be coupled to the SGDs of the plurality of strings.For example, the global SGD line 340 may be coupled to a plurality(e.g., three) of sub-SGD lines 342, 344, 346 with each sub-SGD linecorresponding to a respective subset (e.g., tile column), via acorresponding one of a plurality (e.g., three) of sub-SGD drivers 332,334, 336. Each of the sub-SGD drivers 332, 334, 336 may concurrentlycouple or cut off the SGDs of the strings of a corresponding partialblock (e.g., tile column) independently of those of other partialblocks. A global source-side select gate (SGS) line 360 may be coupledto the SGSs of the plurality of strings. For example, the global SGSline 360 may be coupled to a plurality of sub-SGS lines 362, 364, 366with each sub-SGS line corresponding to the respective subset (e.g.,tile column), via a corresponding one of a plurality of sub-SGS drivers322, 324, 326. Each of the sub-SGS drivers 322, 324, 326 mayconcurrently couple or cut off the SGSs of the strings of acorresponding partial block (e.g., tile column) independently of thoseof other partial blocks. A global access line (e.g., a global CG line)350 may couple the charge-storage devices corresponding to therespective tier of each of the plurality of strings. Each global CG line(e.g., the global CG line 350) may be coupled to a plurality ofsub-access lines (e.g., sub-CG lines) 352, 354, 356 via a correspondingone of a plurality of sub-string drivers 312, 314 and 316. Each of thesub-string drivers may concurrently couple or cut off the charge-storagedevices corresponding to the respective partial block and/or tierindependently of those of other partial blocks and/or other tiers. Thecharge-storage devices corresponding to the respective subset (e.g.,partial block) and the respective tier may comprise a “partial tier”(e.g., a single “tile”) of charge-storage devices. The stringscorresponding to the respective subset (e.g., partial block) may becoupled to a corresponding one of sub-sources 372, 374 and 376 (e.g.,“tile source”) with each sub-source being coupled to a respective powersource.

The NAND memory device 200 is alternatively described with reference toa schematic illustration of FIG. 4.

The memory array 200 includes wordlines 202 ₁ to 202 _(N), and bitlines228 ₁ to 228 _(M).

The memory array 200 also includes NAND strings 206 ₁ to 206 _(M). EachNAND string includes charge-storage transistors 208 ₁ to 208 _(N). Thecharge-storage transistors may use floating gate material (e.g.,polysilicon) to store charge, or may use charge-trapping material (suchas, for example, silicon nitride, metallic nanodots, etc.) to storecharge.

The charge-storage transistors 208 are located at intersections ofwordlines 202 and strings 206. The charge-storage transistors 208represent non-volatile memory cells for storage of data. Thecharge-storage transistors 208 of each NAND string 206 are connected inseries source-to-drain between a source-select device (e.g., source-sideselect gate, SGS) 210 and a drain-select device (e.g., drain-side selectgate, SGD) 212. Each source-select device 210 is located at anintersection of a string 206 and a source-select line 214, while eachdrain-select device 212 is located at an intersection of a string 206and a drain-select line 215. The select devices 210 and 212 may be anysuitable access devices, and are generically illustrated with boxes inFIG. 1.

A source of each source-select device 210 is connected to a commonsource line 216. The drain of each source-select device 210 is connectedto the source of the first charge-storage transistor 208 of thecorresponding NAND string 206. For example, the drain of source-selectdevice 210 ₁ is connected to the source of charge-storage transistor 208₁ of the corresponding NAND string 206 ₁. The source-select devices 210are connected to source-select line 214.

The drain of each drain-select device 212 is connected to a bitline(i.e., digit line) 228 at a drain contact. For example, the drain ofdrain-select device 212 ₁ is connected to the bitline 228 ₁. The sourceof each drain-select device 212 is connected to the drain of the lastcharge-storage transistor 208 of the corresponding NAND string 206. Forexample, the source of drain-select device 212 ₁ is connected to thedrain of charge-storage transistor 208 _(N) of the corresponding NANDstring 206 ₁.

The charge-storage transistors 208 include a source 230, a drain 232, acharge-storage region 234, and a control gate 236. The charge-storagetransistors 208 have their control gates 236 coupled to a wordline 202.A column of the charge-storage transistors 208 are those transistorswithin a NAND string 206 coupled to a given bitline 228. A row of thecharge-storage transistors 208 are those transistors commonly coupled toa given wordline 202.

Memory may be fabricated in decks, and two or more decks may be stackedone atop another. Channel regions of each of the decks may comprisechannel-material pillars, and it may be desired to couplechannel-material pillars of the stacked decks. It would be desirable todevelop improved methods of fabricating stacked memory decks, andspecifically to develop improved methods of coupling channel-materialpillars of stacked memory decks.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a prior art memory device having amemory array with memory cells.

FIG. 2 shows a schematic diagram of the prior art memory array of FIG. 1in the form of a 3D NAND memory device.

FIG. 3 shows a cross-sectional view of the prior art 3D NAND memorydevice of FIG. 2 in an X-X′ direction.

FIG. 4 is a schematic diagram of a prior art NAND memory array.

FIGS. 5-8 are diagrammatic cross-sectional side views of a region of anintegrated assembly at example process stages of an example method forforming an example structure.

FIG. 8A is a diagrammatic top-down view of a region of the integratedassembly of FIG. 8, along the line A-A of FIG. 8.

FIG. 8B is a diagrammatic three-dimensional view of vertically-offsetregions of the integrated assembly of FIG. 8.

FIGS. 9 and 10 are diagrammatic cross-sectional side views of the regionof the example integrated assembly of FIG. 5 at example sequentialprocess stages following process stage of FIG. 8. The process stage ofFIG. 10 shows a region of an example multi-deck memory device.

FIG. 10A is a diagrammatic top-down view of a region of the integratedassembly of FIG. 10, along the line A-A of FIG. 10.

FIGS. 11 and 12 are diagrammatic cross-sectional side views of theexample integrated assembly of FIG. 5 at example sequential processstages following the process stage of FIG. 6. The process stage of FIG.11 may be alternative to that of FIG. 7. The process stage of FIG. 12shows a region of an example multi-deck memory device.

FIGS. 13-17 are diagrammatic cross-sectional side views of a region ofan integrated assembly at example process stages of an example methodfor forming an example structure. The process stage of FIG. 17 shows aregion of an example multi-deck memory device.

FIG. 18 is a diagrammatic top-down view of an example package.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Some embodiments include methods of using some regions of a continuousconductive material of a lower deck as wordlines (routing structures) ofa memory device, and using other regions of the continuous conductivematerial of the lower deck as sacrificial material which is removed toform openings through the lower deck. One or more memory cell materials(e.g., channel material, charge-storage material, etc.) may be formedwithin the opening during fabrication of memory cells of the memorydevice. An upper deck may be formed over the lower deck to form amulti-deck memory device. The openings formed through the lower deck mayextend from openings formed through the upper deck. An inter-deckmaterial may be provided between the upper and lower decks. Theinter-deck material may be “soft”, and specifically may be relativelyeasy to etch as compared to other materials of the upper and lowerdecks. Some embodiments include integrated assemblies (e.g., multi-deckmemory devices) formed utilizing the methodology described above.Example embodiments are described with reference to FIGS. 5-18.

Referring to FIG. 5, an assembly 10 includes a first deck 12 having afirst stack 14 of alternating first and second tiers 16 and 18. Theillustrated region of the stack 14 is only a partial region of thestack, and it is to be understood that the stack may comprise more thanthe illustrated number of tiers 16 and 18.

The first tiers 16 include first and second conductive materials 20 and22. The conductive materials 20 and 22 have different compositionsrelative to one another. In some embodiments, the conductive materials20 and 22 may be metal-containing materials. The first conductivematerial 20 may consist of, or consist essentially of, one or moremetals (e.g., one or more of titanium, tungsten, cobalt, nickel,platinum, ruthenium, etc.). The second conductive material may comprise,consist essentially of, or consist of one or more metal-containingcompositions (e.g., one or more of metal germanide, metal silicide,metal nitride, metal carbide, metal boride, etc.). In some embodiments,the first conductive material 20 may consist of, or consist essentiallyof, tungsten (W); and the second conductive material 22 may comprise,consist essentially of, or consist of one or more of titanium nitride(TiN), tungsten nitride (WN), and tantalum nitride (TaN), where thechemical formulas indicate primary constituents rather than specificstoichiometries.

In some embodiments, the second conductive material 22 may be consideredto be configured as horizontally-extending bars 24 within the firsttiers 16.

The second tiers 18 comprise an insulative material 26. The insulativematerial 26 may comprise any suitable composition(s); and in someembodiments may comprise, consist essentially of, or consist of silicondioxide. The silicon dioxide may have a dielectric constant of about3.9, and accordingly may be of ordinary density associated withrelatively high-quality silicon dioxide.

In some embodiments, the materials 20 and 26 may be referred to as firstand second materials, respectively; with such first and second materialsbeing associated with the first and second tiers 16 and 18,respectively.

In some embodiments, the first tiers 16 may be considered to correspondto conductive levels, and the second tiers 18 may be considered tocorrespond to insulative levels; with the conductive levels andinsulative levels alternating with one another within the stack 14. Inthe illustrated embodiment, each of the conductive levels 16 comprisestwo conductive materials (20 and 22). In other embodiments, each of theconductive levels may comprise only a single conductive material (e.g.,only material 20) or may comprise more than two conductive materials.

The deck 12 has a region 28 extending entirely through the stack 14 ofthe first and second tiers 16 and 18. The first conductive material 20fills such region 28.

The illustrated deck 12 may be formed with any suitable processing. Insome embodiments, the materials 20, 22 and 26 may be deposited as layersstacked one atop another. Such deposition may comprise, for example, oneor more of atomic layer deposition (ALD), chemical vapor deposition(CVD) and physical vapor deposition (PVD). Subsequently, an opening maybe formed through the layers and filled with the conductive material 20to form the illustrated conductive region 28 passing through the deck12.

The deck 12 may be supported by a semiconductor substrate (base). Thesemiconductor substrate is not shown in the figures of this disclosurein order to simplify the drawings. The semiconductor substrate maycomprise any suitable semiconductor composition(s); and in someembodiments may comprise monocrystalline silicon.

Referring to FIG. 6, an inter-deck structure 30 is formed over the firstdeck (lower deck) 14, and a second deck (upper deck) 32 is formed overthe inter-deck structure.

The second deck 32 comprises a second stack 34 of alternating third andfourth tiers 36 and 38. The illustrated region of the stack 34 is only apartial region of the stack, and it is to be understood that the stackmay comprise more than the illustrated number of tiers 36 and 38.

The third and fourth tiers 36 and 38 comprise third and fourth materials40 and 42, respectively. The third and fourth materials are differentcompositions relative to one another.

The fourth material 42 is an insulative material, and in someembodiments may comprise the same composition as the insulative material26 of the first stack 14. Accordingly, in some embodiments the fourthmaterial 42 may comprise silicon dioxide having a dielectric constant ofabout 3.9.

The third material 40 may be a sacrificial material, and may compriseany suitable composition(s). In some embodiments, the third material 40may comprise, consist essentially of, or consist of silicon nitride(SiN), where the chemical formula indicates primary constituents ratherthan a specific stoichiometry.

The inter-deck structure 30 comprises a first inter-deck material 44over a second inter-deck material 46.

In some embodiments, the first inter-deck material 44 may be arelatively “soft” material, meaning that the first inter-deck material44 may be relatively easy to selectively etch relative to the materials40 and 42 of the second stack 34. The first inter-deck material 44 maycomprise, for example, silicon dioxide which etches faster than thesilicon dioxide of material 42 when exposed to ahydrofluoric-acid-containing etchant. In some embodiments, theinter-deck material 44 may comprise silicon dioxide having a lowerdensity than the silicon dioxide of material 42 (e.g., the inter-deckmaterial 44 may be porous silicon dioxide). Additionally, oralternatively, one or more dopants may be provided within the silicondioxide of the inter-deck material 44 to increase an etch rate of suchsilicon dioxide. Suitable dopants may include, for example, one or moreof carbon, boron and phosphorus.

The second inter-deck material 46 may be a relatively “hard” material,meaning that the material 46 may function as an etch-stop for an etchutilized to punch through the materials 40 and 42 of the stack 34. Insome embodiments, the second inter-deck material 46 may comprise,consist essentially of, or consist of aluminum oxide (AlO), where thechemical formula indicates primary constituents rather than a specificstoichiometry.

Referring to FIG. 7, an opening 48 is formed through the second stack34, and through the first inter-deck material 44. The opening 48 stopson the second inter-deck material 46 (i.e., the etch-stop material).

The opening 48 may be patterned with any suitable methodology. Forinstance, in some embodiments a photolithographically-patternedphotoresist mask (not shown) may be utilized to define a location of theopening 48, and the opening 48 may then be formed with one or moresuitable etches. The etches utilized to form the opening 48 may utilizehydrofluoric acid to penetrate silicon dioxide 42 of levels 36, andphosphoric acid to penetrate silicon nitride 40 of levels 38. Thehydrofluoric acid can also be utilized to penetrate silicon dioxide ofthe inter-deck material 44.

In the illustrated embodiment, the inter-deck material 44 is recessed toform cavities 50 which extend under the second deck 32. Such recessingmay be due to the material 44 being “softer” (i.e., more readily etched)than the materials of the stack 32.

Referring to FIG. 8, the opening 48 is extended through the secondinter-deck material 46 to the region 28 (FIG. 7) comprising theconductive material 20, and is then etched through the conductivematerial 20. Accordingly, the opening 48 is formed to extend through thefirst and second decks 12 and 32, and through the inter-deck structure30 between the first and second decks.

In embodiments in which the second inter-deck material 46 comprisesaluminum oxide, the opening 48 may be extended through such secondinter-deck material with an etch utilizing phosphoric acid.

In some embodiments, it can be advantageous to utilize tungsten withinthe region 28 of FIG. 7 as tungsten may be readily removed selectivelyrelative to the silicon-oxide-containing materials 26 and 40, and thesilicon-nitride-containing material 42 (such may be accomplished with,for example, an etch utilizing nitric acid (HNO₃)). The opening 48 hasrelatively straight vertical sidewalls passing through the decks 12 and32, rather than having tapered sidewalls. Such may be advantageousrelative to architectures formed with conventional processing, in thatsuch architectures frequently have tapered sidewalls of openingsanalogous to the opening 48 which can lead to problems in subsequentlyforming materials within such openings.

In the shown embodiment, the cavities 50 are extended under the firstdeck 32 as the opening 48 is passed through the second inter-deckmaterial 46 and through the first stack 14. In some embodiments, thefirst inter-deck material 44 may be considered to be removed fromlateral regions of the inter-deck structure 30 adjacent the opening 28to extend the cavities laterally under the second deck 32. The removalof the first inter-deck material 44 to extend the cavities 50 may occurduring the etching utilized to pass through the material 46 and/orduring the etch utilized to remove material 20 from the region 28.

FIG. 8A shows a top-down view along the line A-A of FIG. 8, and showsthat the opening 48 has a closed-shaped when viewed from above. In theillustrated embodiment, the opening 48 is circular when viewed fromabove. In other embodiments, the opening may have other suitable closedshapes when viewed from above (e.g., elliptical, rectangular, etc.).

FIG. 8B diagrammatically illustrates regions of the opening 48 passingthrough materials 40, 44 and 20 at regions labeled X, Y and Z in FIG. 8.The region Z is within the first deck 12, the region X is within thesecond deck 32, and the region Y is within the inter-deck region 30. Theview of FIG. 8B further illustrates that the cavities 50 extend intoregions between the first and second decks 12 and 32.

The opening 48 may be representative of a large plurality ofsubstantially identical openings formed through the decks 12 and 32 atthe processing stage of FIG. 8; with the term “substantially identical”meaning identical to within reasonable tolerances of fabrication andmeasurement.

Referring to FIG. 9, dielectric-barrier material 60 is formed within theopening 48, charge-blocking material 58 is formed laterally adjacent thedielectric-barrier material 60, charge-storage material 56 is formedlaterally adjacent the charge-blocking material 58, tunneling material(dielectric material, gate-dielectric material) 54 is formed laterallyadjacent the charge-storage material 56, and channel material 52 isformed laterally adjacent the tunneling material 54. The materials 52,54, 56, 58 and 60 may be referred to as memory cell materials.

The channel material 52 may comprise any suitable composition(s); and insome embodiments may comprise, consist essentially of, or consist of oneor more of silicon, germanium, III/V semiconductor material (e.g.,gallium phosphide), semiconductor oxide, etc.; with the term III/Vsemiconductor material referring to semiconductor materials comprisingelements selected from groups III and V of the periodic table (withgroups III and V being old nomenclature, and now being referred to asgroups 13 and 15). In some example embodiments, the channel material 52may comprise, consist essentially of, or consist of appropriately-dopedsilicon.

In the illustrated embodiment, the channel material is configured as anannular ring surrounding an insulative material 62 (e.g., silicondioxide). Such configuration of the channel material may be consideredto correspond to a “hollow” channel configuration (or as a hollowchannel material pillar), with the dielectric material 62 being providedwithin the “hollow” of the channel material configuration. In otherembodiments, the channel material may be configured as a solid pillar,rather than being configured as the illustrated hollow pillar.

The tunneling material 54 may comprise any suitable composition(s); andin some embodiments may comprise one or more of silicon dioxide,aluminum oxide, hafnium oxide, zirconium oxide, etc.

The charge-storage material 56 may comprise any suitable composition(s);and in some embodiments may comprise charge-trapping material; such as,for example, one or more of silicon nitride, silicon oxynitride,conductive nanodots, etc.

The charge-blocking material 58 may comprise any suitablecomposition(s); and in some embodiments may comprise one or more ofsilicon dioxide, aluminum oxide, hafnium oxide, zirconium oxide, etc.

The dielectric-barrier material 60 may comprise any suitablecomposition(s); and in some embodiment may comprise one or more ofaluminum oxide, hafnium oxide, zirconium oxide, etc.

The memory cell materials 52, 54, 56, 58 and 60 may be considered to beconfigured as a pillar 61 which passes through the first and seconddecks 12 and 32. Such pillar may be representative of a plurality ofsubstantially identical pillars that may be formed at the process stageof FIG. 9.

The channel material 52 may be coupled with a conductive sourcestructure (e.g., a source line or source plate) analogous to the sourcestructures described above with reference to FIGS. 1-4. In someembodiments, such source structure may be under the deck 12. The sourcestructure may be comprised by the deck 12, or may be within another deckunder the deck 12.

In the illustrated embodiment of FIG. 9, several of the memory cellmaterials 52, 54, 56, 58 and 60 extend into the cavities 50.Specifically, the dielectric-barrier material 60, the charge-blockingmaterial 58, and the charge-storage material 56 extend into the cavities50. In other embodiments, additional memory cell materials may extendinto the cavities 50, or fewer memory cell materials may extend into thecavities 50.

Referring to FIG. 10, the third material 40 (FIG. 9) is removed from thethird tiers 38 and replaced with conductive regions 64. The thirdmaterial 48 may be removed with any suitable processing, and in someembodiments may be removed with an etch utilizing phosphoric acid. Thethird material may be removed utilizing slits (not shown) providedthrough the second deck 32 in regions laterally adjacent to the pillars61 of the memory cell materials 52, 54, 56, 58 and 60.

The conductive regions 64 comprise a fifth material 66, and a sixthmaterial 68 extending along an outer periphery of the fifth material.

In some embodiments, the fifth material 66 may comprise a samecomposition as the first material 20. For instance, the materials 20 and66 may both comprise, consist essentially of, or consist of tungsten.

In some embodiments, the sixth material 68 may comprise a samecomposition as the second material 22. For instance, the materials 22and 68 may both comprise, consist essentially of, or consist of one ormore of titanium nitride, tungsten nitride and tantalum nitride.

The tiers 36 and 38 may be referred to as conductive levels andinsulative levels, respectively, at the processing stage of FIG. 10;with the conductive levels and insulative levels alternating with oneanother within the stack 34 of the upper deck 32. In the illustratedembodiment, each of the conductive levels 36 comprises two conductivematerials (66 and 68). In other embodiments, each of the conductivelevels may comprise only a single conductive material or may comprisemore than two conductive materials.

First memory 70 cells are within the first stack 14 of the first deck12. The first memory cells include segments of the conductive materials20 and 22 of the first tiers 16, and also include segments of the memorycell materials 52, 54, 56, 58 and 60.

Second memory cells 72 are within the second stack 34 of the second deck32. The second memory cells include segments of the conductive materials66 and 68 of the third tiers 36, and also include segments of the memorycell materials 52, 54, 56, 58 and 60.

The memory cells 70 and 72 may be suitable for utilization in NANDmemory arrays (devices, architectures) analogous to the memory arraysdescribed above with reference to FIGS. 1-4. The assembly 10 of FIG. 10may be considered to be an example configuration of a memory device.

In operation, the charge-storage material 56 may be configured to storeinformation in the memory cells 70 and 72. The value (with the term“value” representing one bit or multiple bits) of information stored inan individual memory cell (70 or 72) may be based on the amount ofcharge (e.g., the number of electrons) stored in a charge-storageregion. The amount of charge within an individual charge-storage regionmay be controlled (e.g., increased or decreased) at least in part, basedon the value of voltage applied to an associated control gate, and/orbased on the value of voltage applied to an associated channel material.The tunneling material 54 may be configured to allow desired tunneling(e.g., transportation) of charge (e.g., electrons) between thecharge-storage material 56 and the channel material 52. The tunnelingmaterial may be configured (i.e., engineered) to achieve a selectedcriterion, such as, for example, but not limited to, an equivalent oxidethickness (EOT). The EOT quantifies the electrical properties of thetunneling material, (e.g., capacitance) in terms of a representativephysical thickness. For example, EOT may be defined as the thickness ofa theoretical silicon dioxide layer that would be required to have thesame capacitance density as a given dielectric (e.g., tunneling material54), ignoring leakage current and reliability considerations. Thecharge-blocking material 58 may provide a mechanism to block charge fromflowing from the charge-storage material to the control gate. Thedielectric barrier material 60 may be utilized to inhibit back-tunnelingof electrons from the control gate toward the charge-storage material.

The memory cells 70 are vertically stacked one atop another within thefirst deck 12. The number of vertically-stacked memory cells 70 may beany suitable number; and in some embodiments may be 8 memory cells, 16memory cells, 32 memory cells, 64 memory cells, 128 memory cells, etc.Similarly, the memory cells 72 are vertically stacked one atop anotherwithin the second deck 32, and the number of vertically-stacked memorycells 72 may be any suitable number.

In the shown embodiment, the second memory cells 72 are verticallystacked over the first memory cells 70.

The segments of the conductive tiers 16 and 36 utilized within thememory cells 70 and 72, respectively, may be considered to be controlgate regions of the memory cells. In some embodiments, the segments ofthe conductive tiers 16 utilized within the memory cells 70 may bereferred to as first control gate regions 74, and the segments of theconductive tiers 36 utilized within the second memory cells 72 may bereferred to as second control gate regions 76.

In the illustrated embodiment, the first control gate regions 74comprise the first conductive material 20 vertically between thehorizontally-extending bars 24 of the second conductive material 22. Thefirst control gate regions 74 have terminal edges 78 which are directlyagainst the dielectric-barrier material 60; and such terminal edgescomprise both the first conductive material 20 and the second conductivematerial 22.

The second control gate regions 76 comprise the conductive material 66(which may be referred to as a third conductive material), and theconductive material 68 (may be referred to as a fourth conductivematerial) along outer surfaces of the conductive material 66. The secondcontrol gate regions have terminal edges 80 which are directly againstthe dielectric-barrier material 60; and such terminal edges onlycomprise the fourth conductive material 68.

The second memory cells 72 are similar to the first memory cells 70, butare not identical to the first memory cells due to the differencesbetween the first and second control gate regions 74 and 76.

The configuration of FIG. 10 may be considered to be a multi-deck memorydevice comprising the vertically-stacked memory cells 70 and 72. Theillustrated memory cells may be comprised by a NAND string, and suchNAND string may be representative of a large number of substantiallyidentical NAND strings formed at the processing stage of FIG. 10 toassemble a NAND architecture analogous to the architectures describedabove with reference to FIGS. 1-4.

FIG. 10A shows a top-down view along the line A-A of FIG. 10, and showsthe memory cell materials 52, 54, 56, 58 and 60 arranged as concentriccylinders along the pillar 61.

In some embodiments, the first deck 12 may be considered to comprisefirst inner lateral edges 82 along sidewalls of the pillar 61, and thesecond deck 32 may be considered to comprise second inner lateral edges84 along the sidewalls of the pillar 61. The inter-deck structure 30 maybe considered to comprise third inner lateral edges 86 which arelaterally offset relative to the first and second lateral edges; andwhich are along the cavities 50. The third lateral edges 86 areassociated with the first inter-deck material 44, and specificallycorrespond to edges where the first material 44 interfaces with thedielectric-barrier material 60.

In the shown embodiment, the second inter-deck material 46 may beconsidered to comprise fourth lateral edges 88. The fourth lateral edges88 are not substantially laterally offset relative to the first andsecond lateral edges 82 and 84; with the term “substantially” indicatingto within reasonable tolerances of fabrication and measurement.

In some embodiments, the cavities 50 (FIGS. 7 and 8) may be avoided bytailoring the various materials of the inter-deck structure 30 and theetching conditions utilized to form the opening 48. FIG. 11 shows aprocess stage analogous to that of FIG. 8, but in which the opening 48has substantially straight vertical sidewalls, rather than comprisingthe cavities 50.

The configuration of FIG. 11 may be subjected to processing analogous tothat described above with reference to FIGS. 9 and 10 to form amulti-deck configuration analogous to that described above withreference to FIG. 10. For instance, FIG. 12 shows the assembly 10 as amulti-deck memory device analogous to the multi-deck memory devicedescribed above with reference to FIG. 10.

In some embodiments, the conductive material 20 of FIG. 5 may berecessed within the region 28 prior to forming the etch-stop material46. Such may improve subsequent etching through the etch stop material46 and the conductive material 20 of region 28. FIG. 13 shows a processstage which may follow the process stage of FIG. 5. The conductivematerial 20 is recessed at a top of the region 28, and subsequently theetch-stop material 46 is formed across the upper tier 16 and across theconductive material 20 of the region 28.

Referring to FIG. 14, the inter-deck material 44 is formed over theetch-stop material 46 to form the inter-deck structure 30, and then thesecond deck 32 is formed over the inter-deck structure 30.

Referring to FIG. 15, the opening 48 is formed to extend through theupper deck 32, and through the inter-deck material 44; with the opening48 stopping on the etch-stop material 46.

Referring to FIG. 16, the opening 48 is extended through the etch-stopmaterial 46 and through the conductive material 20 of the region 28(FIG. 15).

Referring to FIG. 17, the memory cell materials 52, 54, 56, 58 and 60are provided within the opening 48 to form the pillar 61. Subsequently,the material 40 (FIG. 16) is replaced with conductive materials 66 and68 to form a memory device analogous to that described above withreference to FIG. 10.

The memory device configurations of FIGS. 10, 12 and 17 may beincorporated into semiconductor packages. An example semiconductorpackage 90 as shown in FIG. 18. The package 90 may compriseencapsulation material over a semiconductor die 92. The semiconductordie may comprise a memory device configuration formed in accordance withthe embodiments described above. The die 92 is shown in dashed-line(i.e., phantom) view to indicate that the die may be under othermaterials. The package 90 may include pins, pads, wires, etc. (notshown) for electrically coupling circuitry of the die 92 with circuitryexternal of the package 90. Although the semiconductor package 90 isshown comprising only a single die, in other embodiments individualsemiconductor packages may comprise multiple dies.

The assemblies and structures discussed above may be utilized withinintegrated circuits (with the term “integrated circuit” meaning anelectronic circuit supported by a semiconductor substrate); and may beincorporated into electronic systems. Such electronic systems may beused in, for example, memory modules, device drivers, power modules,communication modems, processor modules, and application-specificmodules, and may include multilayer, multichip modules. The electronicsystems may be any of a broad range of systems, such as, for example,cameras, wireless devices, displays, chip sets, set top boxes, games,lighting, vehicles, clocks, televisions, cell phones, personalcomputers, automobiles, industrial control systems, aircraft, etc.

Unless specified otherwise, the various materials, substances,compositions, etc. described herein may be formed with any suitablemethodologies, either now known or yet to be developed, including, forexample, atomic layer deposition (ALD), chemical vapor deposition (CVD),physical vapor deposition (PVD), etc.

The terms “dielectric” and “insulative” may be utilized to describematerials having insulative electrical properties. The terms areconsidered synonymous in this disclosure. The utilization of the term“dielectric” in some instances, and the term “insulative” (or“electrically insulative”) in other instances, may be to providelanguage variation within this disclosure to simplify antecedent basiswithin the claims that follow, and is not utilized to indicate anysignificant chemical or electrical differences.

The terms “electrically connected” and “electrically coupled” may bothbe utilized in this disclosure. The terms are considered synonymous. Theutilization of one term in some instances and the other in otherinstances may be to provide language variation within this disclosure tosimplify antecedent basis within the claims that follow.

The particular orientation of the various embodiments in the drawings isfor illustrative purposes only, and the embodiments may be rotatedrelative to the shown orientations in some applications. Thedescriptions provided herein, and the claims that follow, pertain to anystructures that have the described relationships between variousfeatures, regardless of whether the structures are in the particularorientation of the drawings, or are rotated relative to suchorientation.

The cross-sectional views of the accompanying illustrations only showfeatures within the planes of the cross-sections, and do not showmaterials behind the planes of the cross-sections, unless indicatedotherwise, in order to simplify the drawings.

When a structure is referred to above as being “on”, “adjacent” or“against” another structure, it can be directly on the other structureor intervening structures may also be present. In contrast, when astructure is referred to as being “directly on”, “directly adjacent” or“directly against” another structure, there are no interveningstructures present. The terms “directly under”, “directly over”, etc.,do not indicate direct physical contact (unless expressly statedotherwise), but instead indicate upright alignment.

Structures (e.g., layers, materials, etc.) may be referred to as“extending vertically” to indicate that the structures generally extendupwardly from an underlying base (e.g., substrate). Thevertically-extending structures may extend substantially orthogonallyrelative to an upper surface of the base, or not.

Some embodiments include a method of forming an assembly. A first deckis formed to have a first stack of alternating first and second tiers,and to have a region extending through the first stack. A first materialis within the first tiers and is within the region. A second material iswithin the second tiers. The first material is a conductive material andthe second material is an insulative material. An inter-deck structureis formed over the first deck. The inter-deck structure comprises aninter-deck material. A second deck is formed over the inter-deckstructure. The second deck has a second stack of alternating third andfourth tiers. The third and fourth tiers comprise third and fourthmaterials, respectively. The fourth material is an insulative material.An opening is formed to extend through the second stack and theinter-deck structure, and to the region. The first material is removedfrom the region with an etch selective for the first material relativeto the third and fourth materials.

Some embodiments include an integrated assembly with a first deck thathas first memory cells arranged in first tiers disposed one atopanother. The first deck has first inner lateral edges, A second deck isover the first deck. The second deck has second memory cells arranged insecond tiers disposed one atop another. The second deck has second innerlateral edges. An inter-deck structure is between the first and seconddecks. The inter-deck structure has an inter-deck material with thirdinner lateral edges which are laterally offset relative to the first andsecond inner lateral edges to leave cavities between the first andsecond decks. A pillar passes through the first and second decks and theinter-deck structure. The pillar includes channel material, tunnelingmaterial, charge-storage material, charge-blocking material anddielectric-barrier material.

Some embodiments include an integrated assembly having a first deckwhich has first memory cells arranged in first tiers disposed one atopanother. The first memory cells have first control gate regions whichinclude a first conductive material vertically betweenhorizontally-extending bars of a second conductive material. The secondconductive material is compositionally different from the firstconductive material. The first control gate regions have first terminaledges which comprise both the first conductive material and the secondconductive material. An inter-deck structure is over the first deck. Asecond deck is over the inter-deck structure. The second deck has secondmemory cells arranged in second tiers disposed one atop another. Thesecond memory cells have second control gate regions which include athird conductive material, and which include a fourth conductivematerial along an outer surface of the third conductive material. Thefourth conductive material is compositionally different from the thirdconductive material. The second control gate regions have secondterminal edges which comprise only the fourth conductive material. Apillar passes through the first and second decks and the inter-deckstructure. The pillar includes channel material, tunneling material,charge-storage material, charge-blocking material and dielectric-barriermaterial; the dielectric barrier material laterally surrounding thechannel material, the tunneling material, the charge-storage materialand the charge-blocking material. The first and second terminal edgesare directly against the dielectric-barrier material.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

We claim:
 1. A method of forming an assembly, comprising: forming afirst deck having a first stack of alternating first and second tiers,and having a region extending through the first stack; a first materialbeing within the first tiers and within the region; a second materialbeing within the second tiers; the first material being a conductivematerial and the second material being an insulative material; formingan inter-deck structure over the first deck; the inter-deck structurecomprising an inter-deck material; forming a second deck over theinter-deck structure; the second deck having a second stack ofalternating third and fourth tiers; the third and fourth tierscomprising third and fourth materials, respectively; the fourth materialbeing an insulative material; forming an opening which extends throughthe second stack and the inter-deck structure, and to the region; andremoving the first material from the region with an etch selective forthe first material relative to the third and fourth materials.
 2. Themethod of claim 1 further comprising replacing the third material withconductive regions to form the conductive regions within the thirdtiers.
 3. The method of claim 2 wherein the conductive regions includethe first material.
 4. The method of claim 2 further comprising formingchannel material within the opening; the first deck having first memorycells which include segments of the first tiers together with segmentsof the channel material, and the second deck having second memory cellswhich include segments of the conductive regions of the third tierstogether with segments of the channel material; the first and seconddecks being stacked one atop another, and accordingly the second memorycells being stacked atop the first memory cells.
 5. The method of claim4 wherein the channel material is one of several memory cell materialsformed within the opening; the other memory cell materials includingdielectric-barrier material, charge-blocking material, charge-storagematerial and tunneling material.
 6. The method of claim 5 wherein theforming of the opening through the second stack and the inter-deckstructure removes lateral regions of the inter-deck structure to formcavities under the second stack; and wherein one or more of the memorycell materials extend into said cavities to be directly under a regionof the second stack.
 7. The method of claim 6 comprising incorporatingthe stacked decks into a semiconductor package.
 8. The method of claim 1wherein the inter-deck material is a first inter-deck material, andfurther comprising a second inter-deck material under the firstinter-deck material; the second inter-deck material being an etch-stopmaterial; the forming of the opening through the second stack andthrough the inter-deck material comprising a first etch to extend theopening through the first inter-deck material to the etch-stop material,and comprising a subsequent second etch to extend the opening throughthe etch-stop material.
 9. The method of claim 8 wherein: the firstinter-deck material comprises silicon dioxide; the second inter-deckmaterial comprises aluminum oxide; the first etch utilizes HF; and thesecond etch utilizes phosphoric acid.
 10. The method of claim 1 wherein:the first material comprises a metal; the second and fourth materialscomprise silicon dioxide; the third material comprises silicon nitride;and the inter-deck material comprises silicon dioxide which is lessdense than the silicon dioxide of the third and fourth materials, and/orwhich has a higher concentration of one or more dopants than the silicondioxide of the third and fourth materials.
 11. The method of claim 10wherein the silicon dioxide of the inter-deck material is less densethan the silicon dioxide of the third and fourth materials.
 12. Themethod of claim 11 wherein the silicon dioxide of the inter-deckmaterial is more porous than the silicon dioxide of the third and fourthmaterials.
 13. The method of claim 10 wherein the silicon dioxide of theinter-deck material has a higher concentration of said one or moredopants than the silicon dioxide of the third and fourth materials. 14.The method of claim 13 wherein said one or more dopants are selectedfrom the group consisting of carbon, boron and phosphorus.
 15. Themethod of claim 10 wherein the first material consists of the metal. 16.The method of claim 10 wherein the first material consists of tungsten.17. The method of claim 16 wherein the etch selective for the firstmaterial relative to the third and fourth materials is an etch utilizingnitric acid.